Anti dieseling carburetor structures

ABSTRACT

An anti-dieseling two-stage carburetor structure for a gasoline internal combustion engine. The carburetor includes a solenoid which determines distinct primary throttle blade positions at idle and at ignition-off. A lever system interconnects the solenoid and the secondary throttle plates. Upon opening the ignition circuit of the engine, the de-energized solenoid simultaneously causes the primary throttle plates to close completely and the secondary throttle plates to partially open. The closing of the primary throttle plates stops any fuel flow resulting from airflow through the primary venturis, while the partial opening of secondary throttle plates bleeds air to the intake manifold and eliminates any fuel flow responsive to intake manifold vacuum.

United States Patent [191 Cedar ANTI-DIESELING CARBURETOR STRUCTURES [75] Inventor: Raymond .1. Cedar, Birmingham,

Mich.

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

22 Filed: Oct. 4, 1971 211 App1.No.: 186,370

[52] US. Cl... 123/97 B, 123/198 DB, 123/DIG. 11,

261/26 [51] Int. Cl. F02d 33/00 [58] Field of Search 123/97 B, 198 D, 123/198 DB, 198 DC, 142, 127, DIG. 11; 261/26 A [56] References Cited UNITED STATES PATENTS 2,741,233 4/1956 McKinley 123/97.B 2,724,375 11/1955 Schaffer.. 123/97 B 2,793,001 5/1957 Gallun 123/97 B UX 3,354,877 11/1967 Zub et a1. l23/DIG. 11

[ June 26, 1973 3,357,414 12/1967 Meservc 123/97 B X Primary Examiner-Carlton R. Croyle Assistant Examiner-Michael Koczo, Jr. Attorney- Keith L. Zerschling and Roger B. Erickson 5 7] ABSTRACT An anti-dieseling two-stage carburetor structure for a gasoline internal combustion engine. The carburetor includes a solenoid which determines distinct primary throttle blade positions at idle and at ignition-off. A

lever system interconnects the solenoid and the secondary throttle plates. Upon opening the ignition circuit of the engine, the de-energized solenoid simultaneously causes the primary throttle plates to close completely and the secondary throttle plates to partially open. The closing of the primary throttle plates stops any fuel flow resulting from airflow through the primary venturis, while the partial opening of secondary throttle plates bleeds air to the intake manifold and eliminates any fuel flow responsive to intake manifold vacuum.

5 Claims, 2 Drawing Figures /DZ A PATENIEI] JUN 26 I913 FIGJ.

PIC-3.2

ANTI-DIESELING CARBURETOR STRUCTURES BACKGROUND AND SUMMARY OF THE INVENTION When gasoline internal combustion engines are tuned for low exhaust emissions, increased tendencies to diesel following ignition shut-off have been noted. The invention to be described provides means to eliminate such dieseling by venting the intake manifold to a source of atmospheric pressure immediately following the opening of the engine ignition. This rapidly decays the intake manifold vacuum and interminates the differential pressure responsive idle system fuel feed. The invention further provides means to simultaneously close the primary throttle plates while the secondary throttle plates of a two-stage carburetor are being opened to stop the primary airflow and its corresponding fuel flow.

The invention further provides an anti-dieseling means that is readily adaptable to use with conventional carburetors, that can be easily and economically installed as a field improvement or in initial production and that is reliable andeffective in operation.

A carburetor constructed in accordance with this invention includes primary and secondary barrels formed in a housing. A first shaft extends across a primary barrel and protrudes from the housing. Similarly, a second shaft extends across a secondary barrel and protrudes from the housing. Primary and secondary throttle plates are mounted on the shafts and are pivotal together with their respective shafts to open and close the barrels. A variable position abutment member is fixed relative to the housing and has an element movable to predetermined stop positions. A first lever is secured to the first throttle shaft and is engagable with the abutment member element. A second lever means is secured to the second shaft. A lost motion connection joins the first lever and the second lever to displace the second lever in response to movement of the abutment member element. Upon opening the engine ignition circuit the abutment member assumes a new position. This results in the complete closing of the primary throttle plate to stop any fuel flow resulting from airflow through the primary barrel and the partial opening of the secondary throttle plate to bleed atmospheric air into the intake-manifold and stop any fuel flow resulting from intake manifold vacuum.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawing is a perspective view of a portion of a four-barrel, two-stage carburetor incorporating the invention.

FIG. 2 is a side elevational view taken in the direction ofthe arrow of FIG. 1 and showing certain levers on the side opposite in broken lines.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In the drawings, numeral It) refers to a portion of the housing of a four-barrel, two-stage carburetor. The housing includes an intermediate portion 12 in which the venturis (not shown) are formed and a bottom flange portion 14 which is positioned for attachment on the intake manifold (not shown). A pair of primary throttle plates 16 are mounted on shaft 18 which extends transversely through the carburetor flange 14 and protrudes from both sides. Primary throttle plates'and LII shaft are pivotally mounted to the flange portion and open and close the primary barrels 20 of the two-stage carburetor. Similarly, the secondary throttle plates 22 are mounted on shaft 24 which extends transversely through the carburetor flange and protrudes from both sides. Again, the secondary throttle plates and shaft are pivotally mounted relative to the flange portion to open and close the secondary barrels 26 of the carburetor. Both the primary and secondary plates are biased toward a closed position.

It is to be noted that the invention controls the position and the relationship of the throttle plates only at engine idle and ignition off. It does not affect or interfere with the normal operation and control of the throttle plates during other operations of the carburetor and engine. Consequently, only the throttle plate control levers directly involved in the functioning of this invention will be discussed in the following paragraphs. Other conventional carburetor controls will not be considered.

Lever 28 is affixed to one end of primary throttle shaft 18 and is biased toward an abutment member or solenoid 30. The solenoid has a movable element or armature 32 engagable with the lever 28 at point 29 to position the primary throttle plates 16 in a slightly open position at idle and to completely close the primary throttle plates when the solenoid is de-energized upon opening the ignition circuit 33. The solenoid is spring biased to the closed throttle plate position.

A second lever 34 is secured to the primary throttle shaft 18 on the end opposite lever 28 and is movable together with the shaft and the first lever 28. A third lever 36 is secured to the protruding end ofthe secondary throttle plate shaft 24 on the end adjacent to the second lever 34.

The second lever 34, attached to the primary throttle plate shaft, and the third lever 36, attached to the secondary throttle plate shaft 24, are interconnected by a lost motion connection 38. In the preferred embodiment, the lost motion connection takes the form of a freely rotatable lever mounted to shaft 18 adjacent second lever 34 and engagable with the second and third levers during portions of their travel. The counterclockwise movement of the first lever 28 and second lever 34 from idle to wide open throttle does not affect the position of the lost motion lever 38; however, clockwise movement of the first and second levers from idle position to ignition-off position causes the lost motion lever to be displaced clockwise because of the engagement between the two levers at portion 40. The displacement of the lost motion lever, in turn, displaces clockwise the third lever means 36 because of contact at point 42 and causes the secondary throttle plate 22 to move from a completely closed position to a slightly open position. The operation is explained more fully in the following paragraphs.

OPERATION 16 are slightly open and the secondary throttle plates are completely closed.

When the engine ignition circuit 33 is opened the solenoid is immediately de-energized and the element 32 retracts to its ignition-off position, designated by a line position in FIG. 2. The primary throttle plates are spring biased (by means not shown) toward a closed position, therefore, levers 28 and 34 as a unit are angularly displaced in a clockwise direction. Lever 38, engagable with lever 34 at contact area 40, moves clockwise about the axis-of shaft 18 and engages lever 36 at contact area 42 to displace it in a clockwise direction and slightly open the secondary throttle plates. The spring bias of the secondary plates 22 opposes but is less than that of the primary plates 16.

The effect of these displacements is to check the airflow through the primary barrels of the carburetor and the venturi fuel flow associated therewith and to vent the intake manifold to atmosphere via the secondary barrels and stop the idle system fuel flow dependent on intake manifold vacuum pressure. There is then essentially no fuel being admitted to support dieseling or combustion following ignition shut-off. It is to be noted that the idle system is of conventional design in which a small amount of fuel may be drawn even when the primary throttle plate is closed if a sufficient manifold vacuum is maintained.

Several types of lost motion connections can be used in place of lever 28. For example, lever 34 could be slotted and interconnected to lever 36 by a link having one end slidable with the slot.

Modifications and alterations will occur to those skilled in the art which are included within the scope of the following claims.

I claim: 7

1. In a carburetor for an internal combustion engine,

said carburetor having primary and secondary air fuel induction passages,

primary and secondary throttle valves pivotally mounted respectively within said induction passages to open and close said induction passages,

and means operatively interconnecting said valves operative in response to closing of said primary valve to crack open said secondary valve.

2. In a carburetor for an internal combustion engine,

said carburetor including a housing,

an induction passage formed within said housing,

a throttle valve pivotally mounted within said induction passage to open and close said induction passage,

a variable position abutment member having an element movable relative to said housing to predetermined stop positions,

lever means secured to said throttle valve engagable with said abutment member element,

a second passage communicating said induction passage downstream of said throttle plate with a source of air at substantially atmospheric pressure,

valve means to open and close said second passage,

motion transfer means interconnecting the abutment member element and the valve means to move said valve means and to vent said induction passage in response to movements of said abutment member element.

3. In a carburetor for an internal combustion engine,

said carburetor including a housing,

a primary barrel,

a secondary barrel,

a first shaft extending across said primary barrel and protruding from said housing,

a first plate fixed to said first shaft,

said first plate and shaft being pivotal to open and close said primary barrel,

a second shaft extending across said secondary barrel and protruding from said housing,

a second plate fixed to said second shaft, 7

said second plate and shaft being pivotal to open and close said secondary barrel,

a variable position abutment member fixed relative to said housing having an element movable to predetermined stop positions,

first lever means secured to said first shaft external to said housing engagable with said abutment member element,

second lever means secured to said second shaft external to said housing,

lost motion connection means joining said first level means and said second lever means constructed to displace said second lever means in response to movement of abutment member element.

4. In a carburetor for an internal combustion engine,

said carburetor including a housing,

a primary barrel,

a secondary barrel,

a first shaft extending across said primary barrel and protruding from said housing,

a first plate fixed to said first shaft,

said first plate and shaft being pivotal to open and close said primary barrel,

a second shaft extending across said secondary barrel and protruding from said housing,

a second plate fixed to said second shaft,

said second plate and shaft being pivotal to open and close said secondary barrel,

a variable position abutment member fixed relative to said housing having an element movable to an idle position and an ignition-off position,

first lever means secured to said first shaft external to said housing engagable with said abutment member element and positionable in an idle or ignition-off position,

second lever means secured to said second shaft external to said housing,

lost motion connection means joining said first lever means and said second lever means constructed to displace said second lever during the range of displacement of said first lever means from idle to ignition-off position.

5. In a carburetor for an internal combustion engine,

said carburetor including a housing,

a primary barrel,

a secondary barrel,

a first shaft extending across said primary barrel and protruding from said housing,

a first plate fixed to said first shaft,

said first plate and shaft being pivotal to open and close said primary barrel,

a second shaft extending across said secondary barrel and protruding from said housing,

a second plate fixed to said second shaft,

said second plate and shaft being pivotal to open and close said secondary barrel,

a solenoid fixed relative to said housing having an element movable to an idle position and an ignitionoff position,

first lever means secured to said first shaft external to said housing engagable with said solenoid and positionable in an idle or ignition-off position,

second lever means secured to said secondshaft external to said housing,

third lever means slidably mounted to said first shaft and engagable with said first lever means to move therewith during its range of displacement from 

1. In a carburetor for an internal combustion engine, said carburetor having primary and secondary air fuel induction passages, primary and secondary throttle valves pivotally mounted respectively within said induction passages to open and close said induction passages, and means operatively interconnecting said valves operative in response to closing of said primary valve to crack open said secondary valve.
 2. In a carburetor for an internal combustion engine, said carburetor including a housing, an induction passage formed within said housing, a throttle valve pivotally mounted within said induction passage to open and close said induction passage, a variable position abutment member having an element movable relative to said housing to predetermined stop positions, lever means secured to said throttle valve engagable with said abutment member element, a second passage communicating said induction passage downstream of said throttle plate with a source of air at substantially atmospheric pressure, valve means to open and close said second passage, motion transfer means interconnecting the abutment member element and the valve means to move said valve means and to vent said induction passage in response to movements of said abutment member element.
 3. In a carburetor for an internal combustion engine, said carburetor including a housing, a primary barrel, a secondary barrel, a first shaft extending across said primary barrel and protruding from said housing, a first plate fixed to said first shaft, said first plate and shaft being pivotal to open and close said primary barrel, a second shaft extending across said secondary barrel and protruding from said housing, a second plate fixed to said second shaft, said second plate and shaft being pivotal to open and close said secondary barrel, a variable position abutment member fixed relative to said housing having an element movable to predetermined stop positions, first lever means secured to said first shaft external to said housing engagable with said abutment member element, second lever means secured to said second shaft external to said housing, lost motion connection means joining said first level means and said second lever means constructed to displace said second lever means in response to movement of abutment member element.
 4. In a carburetor for an internal combustion eNgine, said carburetor including a housing, a primary barrel, a secondary barrel, a first shaft extending across said primary barrel and protruding from said housing, a first plate fixed to said first shaft, said first plate and shaft being pivotal to open and close said primary barrel, a second shaft extending across said secondary barrel and protruding from said housing, a second plate fixed to said second shaft, said second plate and shaft being pivotal to open and close said secondary barrel, a variable position abutment member fixed relative to said housing having an element movable to an idle position and an ignition-off position, first lever means secured to said first shaft external to said housing engagable with said abutment member element and positionable in an idle or ignition-off position, second lever means secured to said second shaft external to said housing, lost motion connection means joining said first lever means and said second lever means constructed to displace said second lever during the range of displacement of said first lever means from idle to ignition-off position.
 5. In a carburetor for an internal combustion engine, said carburetor including a housing, a primary barrel, a secondary barrel, a first shaft extending across said primary barrel and protruding from said housing, a first plate fixed to said first shaft, said first plate and shaft being pivotal to open and close said primary barrel, a second shaft extending across said secondary barrel and protruding from said housing, a second plate fixed to said second shaft, said second plate and shaft being pivotal to open and close said secondary barrel, a solenoid fixed relative to said housing having an element movable to an idle position and an ignition-off position, first lever means secured to said first shaft external to said housing engagable with said solenoid and positionable in an idle or ignition-off position, second lever means secured to said second shaft external to said housing, third lever means slidably mounted to said first shaft and engagable with said first lever means to move therewith during its range of displacement from idle to ignition-off positions, said third lever means being engagable with said second lever means during the range of travel of said first lever from idle to ignition-off positions to displace said second lever and said secondary throttle plate from a closed position to a partially open position. 